Ultrasonic scanner for in vivo measurement of cancellous bone properties from backscattered data

Abstract

A dedicated ultrasonic scanner for acquiring RF echoes backscattered from the trabecular bone was developed. The design of device is based on the goal of minimizing of custom electronics and computations executed solely on the main computer processor and the graphics card. The electronic encoder-digitizer module executing all of the transmission and reception functions is based on a single low-cost field programmable gate array (FPGA). The scanner is equipped with a mechanical sector-scan probe with a concave transducer with 50 mm focal length, center frequency of 1.5 MHz and 60% bandwidth at -6 dB. The example of femoral neck bone examination shows that the scanner can provide ultrasonic data from deeply located bones with the ultrasound penetrating the trabecular bone up to a depth of 20 mm. It is also shown that the RF echo data acquired with the scanner allow for the estimation of attenuation coefficient and frequency dependence of backscattering coefficient of trabecular bone. The values of the calculated parameters are in the range of corresponding in vitro data from the literature but their variation is relatively high.

Ultrasound Speed of Sound Measurements in Trabecular Bone Using the Echographic Response of a Metallic Pin

“…However, precise differentiation of the echo of the pin inserted in bone tissue remains difficult because of the complex echographic response of the trabecular structure (Litniewski et al 2012). Therefore, the signal corresponding to the ultrasonic response of bone tissue located between the pin and the transducer is removed by considering the echo of the pin only given by…”

Signal of Interest Selection Standard for Ultrasonic Backscatter in Cancellous Bone Evaluation

“…Although most research has indicated that backscatter is positively related to cancellous bone status (i.e., BMD, BV/TV and ultimate strength) (Karjalainen et al 2009(Karjalainen et al , 2012Litniewski et al 2012;Moayyeri et al 2012;Riekkinen et al 2007;Wear et al 2012;Zhang et al 2013), some studies have reported a negative correlation (Hoffmeister 2011a;Hoffmeister et al 2000Hoffmeister et al , 2006Hoffmeister et al , 2008Hoffmeister et al , 2011. This contradiction has confused researchers and has obstructed clinical applications of ultrasonic backscatter for cancellous bone assessment.…”

Effect of intervening tissues on ultrasonic backscatter measurements of bone: An in vitro study

“…Indeed, a number of backscatter studies have been performed at the hip and spine of human volunteers. [5][6][7][8] Backscatter occurs as an ultrasonic wave interacts with the trabecular microstructure of cancellous bone. The conventional approach is to measure the backscatter coefficient or the frequency averaged backscatter coefficient from cancellous bone.…”